This invention relates to a fuel injection apparatus in an internal combustion engine used for a vehicle such as a motorized two-wheeled vehicle or the like.
There has been proposed in Japanese patent application No. 150601/Showa 52(1977) as an apparatus of this kind such a type that an intake passage for an internal combustion engine is provided, on a downstream side of a throttle valve, with a fuel injection nozzle connected through a fuel passage to a fuel pump and is provided, on an upstream side of the throttle valve, with an air metering valve which is so arranged that, by means of a negative pressure responsive member which is to be operated in response to an intake negative pressure at an intermediate portion between the member and the throttle valve, the same may be operated to turn towards its opening side according to increase in the intake negative pressure, so that by turning of the air metering valve, a fuel metering valve interposed in the fuel passage is opened through a lever arranged to be operated in conjunction with a cam mounted on a rotary shaft of the air metering valve, and consequently a desired amount of fuel according to a profile of the cam is injected according to change in an intake air amount.
It has been usual in this case that the fuel metering valve is formed into a rotary valve, and a valve shaft thereof is arranged to be in parallel with the turning shaft of the air metering valve and the lever which is in engagement at its forward end with the cam is attached at its base end to the valve shaft, so that the fuel metering valve may be turned according to turning of the cam. With this arrangement, it has been in general that a valve body of the air metering valve is formed into a long one extending in a direction making a right angle to the turning shaft, and a valve body of the fuel metering valve is formed into a long one extending in the axial direction of the valve shaft. Accordingly, for arranging the valve shaft and the turning shaft in parallel one with another, it is necessary that the valve bodies of the two metering valves are at right angles one to another, so that there is caused such an inconvenience that the apparatus requires a comparatively large space.